The Latest: Swedes warned against trips to North Korea

The Latest on tensions created by North Korea's nuclear weapons program (all times local):

6:10 p.m.

Sweden has urged its citizens to refrain from unnecessary trips to North Korea following the country's sixth and most powerful nuclear test to date.

The announcement by the Swedish Foreign Affairs Ministry on Friday came hours after Mexico's government said it declared North Korean Ambassador Kim Hyong Gil as persona non grata and ordered him to leave the country within 72 hours in response to Sunday's nuke test.

The United States has already banned Americans from traveling to North Korea following the death of Otto Warmbier, a 22-year-old college student from Ohio who was released from North Korea in June in a coma after being detained there for more than a year.

Sweden has had diplomatic relations with North Korea since 1973. The Swedish Embassy in Pyongyang also provides consular services for the United States, Australia and Canada.

South Korea is closely watching North Korea over the possibility it may test-launch an intercontinental ballistic missile as soon as Saturday when it celebrates its founding anniversary.